TITLE: GCN CIRCULAR NUMBER: 41866 SUBJECT: GRB 250918A: BALROG localization (Fermi Trigger 779891543 / GRB 250918522) DATE: 25/09/18 13:33:35 GMT FROM: Jochen Greiner at MPE <jcgrog@mpe.mpg.de> T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 779891543 at 12:32:18 on 18 Sept. 2025 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position is: RA(2000.0) = 225.6 deg Decl.(2000.0) = -16.2 deg The 1 sigma statistical error radius is 4.1 deg. We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB250918522/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB250918522/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB250918522/json View this GCN Circular online at https://gcn.nasa.gov/circulars/41866. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...